Are Sony E-Mount lenses all that bad?

Hi all, I currently own a NEX 5n with kit & 50mm Emount lenses. I've seen in a whole lot of forums, great bashing against emount lenses, and incredible praises towards Olympus mainly.

Is the quality between these brands (lenses wise) all that different? I know the 75mm 1.8 Olympus just released is astonishing, but that's 800 USD.

Is the Quaility on the Oly 45mm 1.8, all that different from Sony's SEL50?

Hope someone can throw some light into this!